


In My Depths

by inujuju



Category: Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Alternate Universe, Alternate Universe - Merpeople, Anal Sex, Bottom Claude von Riegan, Claude is a Sea Dragon, Dimitri is a Shark, EGGS FOR THE PEOPLE, M/M, Oviposition, Top Dimitri Alexandre Blaiddyd, Weird Biology
Language: English
Status: Completed
Published: 2020-04-14
Updated: 2020-04-14
Packaged: 2021-03-01 17:15:46
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,863
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23640685
Author URL: https://archiveofourown.org/users/inujuju/pseuds/inujuju
Summary: In the Summer matting season, Dimitri seeks the solitude of the ocean depths. Away from his family and all he knows, he encounters a stranger. One has needs similar to his own.
Relationships: Dimitri Alexandre Blaiddyd/Claude von Riegan
Comments: 25
Kudos: 221





	In My Depths

**Author's Note:**

  * For [Silmarwen](https://archiveofourown.org/users/Silmarwen/gifts).



> Blaming @nightfuys and @silmarwen_t (Silmarwen). 
> 
> Particulary Silmarwen because this is, in a way, her long awaited request.

The warming summer waters provide a stark contrast to the thawing lands of Dimitri's people. The mermaid watches as they dance on the land, singing praises to his kind for the bountiful sea feast they have provided. In return, the humans accept the merfolk onto the shore with reverence and praise. Sylvain is already swimming around them on bewitched legs, asking every lady to dance with him.

They are all seeking mates, this time of year. Yet despite the smile the humans bring to Dimitri's face, he has no interest in them. He yearns, once more, for the heart of the ocean, for the twisting currents that test his power. They chart a course only for him, one that he desires to travel with a bride. The humans cannot transform their legs into tails, and even then, the love of the land will call them home. The sea is not their place.

He swims to the docks to greet Mercedes. The human from the south is kind and understanding, so unlike the conquerors of her blood. She is one of the few that none of his folk will try to ensnare with sweet words. They have no chance, for her words are forever sweeter. Even now, as Dimitri passes off his garland of coral to her, she speaks with acceptance.

"You do not plan to join the dance, Dimitri?" Mercedes asks, resting the garland in her lap. She adjusts the wet flora so that it will dry to something far more beautiful.

"I enjoy watching it from afar." He replies, looking back to the shore as Ashe offers a hand to Felix. Ingrid's tail has already transformed to that of a humans, and she laughs as Felix grumbles through the process. "They are far more happy without me fumbling around like a newborn."

Mercedes frowns. "You shouldn't sacrifice your happiness for the convenience of others, your highness."

The prince shakes his head. "I apologize, I did not mean to say it in such a manner. I do not favor human legs, and thus have never grown accustomed to them."

"I understand." Mercedes says with a smile. "It is hard to adjust to something you are not used to, even more so if you dislike it."

In the pleasant lull between them, Dimitri finds his eyes straying to the ocean. Out in the deeper waters, waves crash with a more viscous temper. One that Dimitri yearns to get lost in.

"You can go." Mercedes says in a whisper. "I won't tell anyone."

Dimitri glances at his human friend, and then at his people on the beach, pairing up with the humans.

"Do you think there is something wrong with me, to prefer the solitary sea over the joyous celebration before me?"

Mercedes taps her chin in thought. "I don't think there's anything wrong with you, to have a preference that differs from others. It's what makes you, you, after all." Her smile is warm. "Besides, the sea is far to vast for it to truly be lonely, don't you think?"

Dimitri smiles back at her, reaching up to lean his head against her offered hand. They cannot give a full embrace without causing discomfort, so they settle for a more formal way to say goodbye.

With one last glance at the shore, Dimitri swims out sea, dives beneath the surf, and lets the current take him into its depths.

* * *

At the center of the Great Bay of Fodlan lays a particular hotspot, one that Dimitri tends to avoid due to its unstable nature. The currents from four vastly different beaches clash here. They bring a wide variety of life, vivid colours and strange mannerisms.

Dimitri has met a few merfolk from the Alliance to the east of his territory. The hotspot is something of a neutral zone, no group able to properly occupy the water with the alternating tides. At this time of year, the spot is still frigid from winter's cold spell, slower to warm than the coastal areas. It is easy for Dimitri to mindlessly drift in these waters, to let the heaviness maneuver him wherever it pleases.

This deep in the water, Dimitri can barely see the shimmering rays of the sun. Had his family been with him they would surely drag him upwards, all the way to the surface, trying to get fresh air into him to clear his head. But alone, Dimitri lets his gills flare wider, fluttering as he takes in the thicker particles of oxygen. There's something thrilling, about being so deep in the ocean that he can feel his body adjust to the pressure.

There are other changes too, ones that he is not as keen to notice. His eyes, normally like a humans, become darker. His pupils widen, dulling color to better make out movement. At the point where true darkness grasps up at him, he is more instinct than reason.

Something flutters beneath him. It reminds Dimitri of seaweed, a dark grey-green color. Outside of the odd flicker of brightness, it blends in perfectly. Those sparks of gold is what draws Dimitri's eyes. When small fish brush against the ribbon-like material, it twists to reveal a very different underside.

He maneuvers himself above the odd plant. It cannot be seaweed, this deep in the ocean. Nor can it be some kind of moss, with the frigid temperatures. When Dimitri is directly above it, he can take in the length, little more than half his own. It doesn't smell like anything Dimitri has ever come across. He cannot deny that there is something to the scent that interests him, that draws him closer to the other. The smaller fish have scattered with Dimitri's descent, no longer present to bump against the plant. Dimitri's swimming, however, is causing enough ripples that it should move as before. And yet, it is suspiciously still.

Dimitri cannot deny his curiosity. He slows his body, letting the ocean pull him down. When he is closer enough to touch, he reaches out, tempered excitement at what he may find.

He doesn't make contact before it moves.

The figure below him twists, turning the dark green into blinding gold. Arms push forward, grabbing onto Dimitri and pulling him against a cold body. Dimitri forgets to flail at the movement, to strike against the stranger. A tail, long and foreign, twists around Dimitri's own, stroking him in a way that causes his eyes to flutter and a moan to echo out. His own arms come to grab the creature, pulling it flush against him as his body responds to the warming waters.

"What's a great shark like you doing down here?" A mumble sounds against his ear.

Dimitri takes a while to steady himself, large gills fluttering for oxygen. The other merfolk doesn't rush him. Instead, it strokes Dimitri's back, carefully tracing the scars present there.

"I was curious," Dimitri finally answers "to see what lurked down here."

"Hmm," The other's voice is soft, captured in Dimitri's ears. "Well, what do you think?"

The other doesn't move away from Dimitri, but the shark is alright with that. His eyes are still closed, taking in the smell and sound of the other. He moves his hands around, feeling the branching leaves that he thought belonged to a plant. They are far harder than he imagined. Instead of twisting at his prodding, they resist to an extent, crafted from thin bone and leather skin.. Yet every now and then, he will come across a sensitive nub that contracts muscle and bends the carapace like a wave.

The stranger's laughter tickles Dimitri's ears as he keeps exploring. The other's back lacks the dorsal fin of Dimitri's kind. Instead, protective spines lay flat. Along the spine, an array of small plates wave, flattening at Dimitri’s touch. The ridges, Dimitri notices, ends prematurely.

"Something a bit deeper tried to eat me a few days ago." The stranger answers as Dimitri caresses the tips. "I'm not the fastest of swimmers, so I gave it something to keep it busy."

Dimitri hums in reply, enjoying the echoing sound.

"Will you let me get a better look at you?" He asks, keeping his eyes closed in a strange promise.

The stranger laughs. "I don't mind, big guy. But I would prefer it if you took me to warmer waters before you ate me."

Dimitri frowns, wiggling his tail free from the other’s grip. "I do not plan to do such a thing. Why would you expect that?"

"You know," the other giggles, "there is more than one meaning to eating someone, your horniest."

Dimitri sputters in reply, letting go in shock at the audacity of the other. The sea dragon, for that is what the stranger must be, keeps his grip glued to Dimitri's torso. With a grumble, Dimitri accepts his passenger. Swimming closer to the surface, Dimitri tracks the currents before heading back home.

"My name's Claude, by the way." The stranger greets. "I come from warmer waters than this, as you can probably tell."

"You are cold." Dimitri replies, arms wrapping around the other as he swims. It's pleasant and Dimitri doesn't notice how he nuzzles against Claude. He laughs. "I'm Dimitri. I am one of the guardians of the western shores."

"Oh wow, I really got pulled out far then."

Dimitri pauses, "do you want me to-"

"Nah, wherever you're going is fine. I don't really have a home back east. I just drift around."

Dimitri moves a hand against the sea dragon's strange fins. "You don't seem to be truly built for swimming."

Claude sighs. "You're not wrong, so I won't argue. I think I'm supposed to live among coral palaces or something. Sadly, there weren't any that matched my majesty back there.."

"We do have one coral reef in our area. There aren't any other merfolk who reside there, so you are welcome to call it home."

"I wouldn’t say no, but are you sure that's okay, big guy? Sounds like prime territory." Claude wraps his arms around Dimitri's shoulders, pulling himself closer to Dimitri's ear. "Though if you're trying to seduce me, you're definitely on the right path."

Dimitri lets out a splinter of air, the water vibrating with his displeasure. If anything, it seems to encourage Claude, who wraps his strange tail around Dimitri's waist.

"Come on, I'm smart enough to notice it's mating season for you guys. Mine just so happens to line up with yours. Shouldn't you take advantage of that?" He rubs his lower half against Dimitri. "I'm curious to see what a shark like you has hidden under your fins."

Dimitri grabs at Claude, pushing him hard against his waist. His sharp claws dig into the other's plant-like plates, causing Claude to hiss. Dimitri doesn't slacken his grip at the sound, smelling the arousal slipping out of Claude.

"I'd prefer I get you to a refuge first." Dimitri explains, voice deep.

Claude trills in response, somehow pressing closer. "Romantic."

Dimitri picks up the refreshing scent of the shore, taking in the fading smell of his family. Claude twists closer to him, nuzzling against his neck. His body has started to shake slightly, causing Dimitri to shift their alignment so he can better smooth the other's back spines.

"You're going to cut yourself." Claude says with a grumble, pushing his face against Dimitri's neck. "That'll make them worse, I’m sure."

"They're all on land." He explains. "And even if they were here, I would not allow them to touch you."

Claude's voice fights against laughing bubbles. "Don't let me be the cause of any more family drama. I don’t think I can handle any more of that."

"You aren’t.." Dimitri says, continuing the careful strokes against the other's back. "I'll mate you tonight and then no one can deny your importance to me."

Claude is silent for the rest of the trip, his fin plates fluttering out and spines relaxing in time. There's something... pleasant, about swimming with Claude. He adjusts his body to the current, helping Dimitri master the tides in ways he didn't think was possible. When they fight against it, Claude stretches out his body to provide resistance, and when they move with it, he flattens into a glide.

"I would like to see you swim, sometime. I am certain it is a gorgeous site."

Claude shrugs. "If you're alright with a sea urchin's pace. As you said, I'm not built for swimming."

"And yet, you seem skillful at it."

Dimitri can feel Claude smile against his skin. "I'm just good at going where I want to be. That being said, we are getting pretty close to the shore, big guy."

"The refuge is in a cove, just off of a minor inlet. There are tide pools made from sandstone and lichens that are sure to meet your refined tastes."

Claude laughs at Dimitri's words, body relaxing further. "I know I teased you about mating, but you've really warmed up to the idea, haven't you?"

Dimitri nuzzles against Claude's hair. "I see no reason not too, if you are willing."

"You _do_ know my kind are a bit more paternal that you sharks, right?"

"Are they?" Dimitri asks, settling a hand against Claude's spines.

Claude doesn't answer.

Dimitri draws them through the narrow passage of the inlet. He dives under a bridge of rock and rises in the promised cove. The water is slow and steady, allowing Claude to release his grip on Dimitri. With reluctance, Dimitri lets go as well.

Finally apart, Dimitri can take in Claude's appearance to a greater extent. The sea dragon’s coloring is akin to freshly watered soil, his eyes as bright as summer leaves. The colorful ridges that form his strange fins show-off two colors. On the top, they are that dark, seaweed green, while beneath, they are a blinding gold. In the light of the sun, Dimitri can see intrinsic patterns that mimic coral foliage. Had Claude been drifting on the edge of a coral reef, he would have thought him to be nothing more than a large collection of plants.

What a clever appearance for a skimmer of the deep. Camouflaged from both those below and above.

Claude’s nails are dull in contrast to Dimitri's claws. When Claude smiles, it's with teeth more like a humans than Dimitri's own. Despite that, he does not doubt Claude's jaw is stronger. The spines that line his back straighten up and down, thin needles that could probably slice through a school of fish with ease. Dimitri's thicker skin along his back may even be in danger.

"Having second thoughts?" Claude asks, fluttering his eyes at Dimitri. Yet the tense way his body stills portrays Claude’s own nerves.

The shark grins. "Not in the slightest." Dimitri surges forward, twisting his more agile body around the startled Claude. To his testament at being mated, he doesn't shoot out his spines taking obvious breaths to keep them flat against him. Dimitri nudges against the other, his fragile stomach resting against Claude's back. He can feel the flutter of _heat_ near Claude's tail.

"T-Tide pools, right?" Claude says, words breaking apart in the water.

Dimitri grins, brushing his sharp teeth against Claude's neck.

"You can take us there, can't you?" He teases, guiding Claude's gaze to their destination.

Claude whines, a high sound that vibrates against Dimitri, electing a moan and a nip. Claude shivers against him, his spines teasing Dimitri's nerves.

"For someone who was so flirtatious, you seem so shy now."

"S-Shut up and help me out." Claude says, tail and back arching to move them closer to the pools. Dimitri makes a sound akin to a purr, warm and all-encompassing in the water. When Claude finally gets to the pool's ridge, Dimitri takes pity on the other. He pulls them over, pushing Claude against the smooth lichen bottom.

Their heads both surface as Dimitri presses them together. Claude's body seizes as it takes in air with a gasp. His voice sounds all the more beautiful in the fresh air, a treat that can only come from mating with a merfolk.

Claude grabs onto the shore's ridge, holding himself above water as Dimitri presses against his back. The sea dragon twists his tail away, wrapping it around Dimitri's waist in a vice grip. The heat pressing against Dimitri elects a growl that fills the air. Claws sink into Claude's fin plates, electing human moans from his lips.

"You're meant for me, aren't you beloved?" Dimitri says, grinding against Claude's lower half. "So eager for my eggs already, can you even hold them all?"

Claude shivers against Dimitri, mouth flapping between moans and gasps. Dimitri trails a hand up the other's body, teasing a nipple on his way to the other's mouth. Claude opens without resistance, taking Dimitri's fingers in like a starved creature. The slick pouches aren't in the same spot as a shark's, but Claude urger's Dimitri's fingers to the back of his throat. The sea dragon chokes against the intrusion, but Dimitri stays vigilant, rubbing against the thick sac that steals Claude's breath.

Once Dimitri's fingers are coated in the pink gel, he slips his hand away. He holds Claude above the water, letting him catch his breath. He's shaking with need, pressing against Dimitri's pectoral fins that elects moans from the shark.

"Dimitri, please." Claude whines, tightening his tail on Dimitri's waist.

"Patience, love." Dimitri says, biting Claude's ear and electing another groan. "You're not even open for me yet."

"P-Please." Claude says again.

Dimitri rubs the gel just below Claude's tail, causing the sea dragon to whine. Claude thrashes as Dimitri tricks his body into opening himself for a female's eggs. Once the hole puckers, Dimitri presses a finger in, just to tease the other.

"D-Dimitri!" Claude cries. "Please, please, please. Give me your eggs already." He's half delirious, mind overrun by the summer heat and Dimitri's heavy body on top of him.

Dimitri pulls Claude back for a kiss. Their tongues press into one another, vicious and hungry. Dimtiri loves the feeling of Claude writhing against him, half in water and half in air, like he's always wanted it to be.

Letting go of the other, Dimitri presses hard against Claude's ass, groaning as his dicks finally slip past his pectoral fins. The effortless glide into Claude's warm hole is heaven, Dimitri's clasper gripping the smaller merfolk beneath him to keep him still. The heat of the other is overwhelming, encouraging Dimitri to push in deeper.

Claude moans, arching his back. His spines flicker dangerously against Dimitri, but they never fully flare. Instead they slide against each other into a comforting bed of leather-like skin for Dimitri to lay upon.

Dimitri lets his free hands explore Claude's chest, pulling whines from him as he twists his nipples and claws at sensitive flesh. He thrusts into Claude's moist cavern again and again, grunting with each push. Claude answers with moans, with cries, riding against the current Dimitri has created into their pool.

"C-Come on already, Dimitri." Claude whines, lips shining with saliva as he turns his head towards the other. "Give me your eggs al-"

Dimitri cuts the other off, throwing his lips against Claude’s. He bites, drawing blood, and sucks at the sensitive flesh. Claude shakes at the violence mating with a shark bring. Something _gives_ from inside of Claude. The water clouds into a pink, soft and delicate like coastal flowers.

The sight, the _smell_ of the other’s release draws the madness out of Dimitri. He pushes harder, pulling practically out before pressing back in. Claude's body sings around him, encouraging his cock to climax.

Dimitri feels the precipice, the shifting of the current as a giant wave forms. Claude twists his body perfectly in time with Dimitri’s cries. The vice grip his tail has on Dimitri forces the other against the lichen-covered stone and allows Claude to use his whole weight to force Dimitri _deeper_.

The shark cries out, arching up against his mate and scratching at Claude's hips. His spend shoots out of him, causing Claude to moan and shake from the sensation. The sea dragon starts to fall, but Dimitri recovers in time to grasp him, to hold the other close as he rolls them over.

"You beautiful thing." Dimitri mumbles into the other’s ear. "What were you trying to do, with a trick like that?"

Claude speaks but his words don't form. Instead his body is focused on pulling Dimitri in further, on encouraging the other to finally stuff him.

Dimitri is happy to oblige.

He has seven eggs in his sac, and he rolls against Claude in a motion like a wave. The tide pulls against them as the sun sets, and Dimitri drowns Claude in praise as they move together. The first egg is difficult, Claude's body squirming from the _size_ of it.

"D-Dimitri..." Claude whimpers.

The shark soothes with nips, electing groans out of the other. "Open up for me, Claude. You want them, don't you?"

"Yesss." Claude answers in a daze, his tail flexing against Dimitri.

"Then open up for me."

Claude breathes through it, relaxing against Dimitri. When the water rushes in, dunking them under, Claude's body goes supple, content and pleased. The first egg pushes through. Dimitri encourages it deeper with his hand, taking on the active role in the courtship as Claude's mind hazes over from the egg inside him. When the second one pushes, Claude's body relaxes in time to accept it. Dimitri praises Claude further, rubbing against the growing bulge in his stomach.

Five eggs settle inside Claude comfortably, but Dimitri still has two left. He hesitates, clasper starting to loosen its hold.

"Dima..." Claude says with a slur. "There's a few left, right? I want all of them."

"But, Claude, you-"

"They'll fit." He reassures, voice sounding more aware as Claude breathes through his nose. "They will, love, so please. I want them, all of them. I want to be yours fully."

Dimitri whines at the words, pressing his face against Claude's back in embarrassment. He can't stop the roll of his hips. Claude loosens even further, pressing against his belly with their hands interlaced to move what's already inside further up.

With a cry, Dimitri pushes in the sixth egg, the sound echoed by Claude. They take a moment to breath, to moan and kiss and ease one another. Then Dimitri pulls Claude tight against him, stretching the sea dragon even further to force the last egg in.

Claude's moans break into hiccups, and Dimitri licks his tears away. The sea dragon is horribly full, body stretched to his limits. Despite that there is a delirious smile on his face. When Dimitri slips out, Claude loosens his tail from the other and slowly turns around.

"T-Told you." Claude says, voice quiet from the strain inside him.

Dimitri huffs against the other's lips. "Look at you, my little trickster. Did you get what you wanted?"

Claude's eyes flicker close and a soft, pleasant sound vibrates against his lips. "You promised me a palace."

Pressing a kiss to the other, Dimitri whispers "of course, my queen."

**Author's Note:**

> Biology? What's that? Just a means to write funky sex.


End file.
